Fluidized bed multistage charring regeneration device and regeneration method

Abstract

This invention discloses a fluidized bed multi-stage coke regeneration device, comprising a first regenerator, a second regenerator, a low-pressure-drop large-hole distribution plate and a third regenerator disposed between the two. The first regenerator has a first inclined inlet pipe for the catalyst to be generated, and the second regenerator has a second inclined inlet pipe for the catalyst to be generated. The third regenerator contains a partitioned cylinder with a gap between the partitioned cylinder and the bottom of the third regenerator. A catalyst dilute phase conveying pipe is located within the partitioned cylinder, and a catalyst distributor that sprays catalyst downwards within the partitioned cylinder is located at the top of the conveying pipe. A third main air distributor is located within the partitioned cylinder, and a fourth main air distributor is located within an annular guide zone. A regenerated catalyst outlet inclined pipe is located on the cylinder wall where the annular guide zone is located. A first regeneration circulation pipe is located on the cylinder wall where the annular guide zone is located and connected to the bottom of the first regenerator. This invention also discloses a fluidized bed multi-stage coke regeneration method. This invention employs multi-stage series regeneration, saving coke combustion air consumption and reducing engineering investment.

Description

Technical Field

[0001] This invention relates to a petroleum hydrocarbon catalyst regeneration or pulverized coal coking technology, specifically to a fluidized bed multi-stage coking regeneration device and regeneration method. Background Technology

[0002] With the increasing trend of heavier and lower-quality feedstocks, the catalytic cracking or catalytic pyrolysis of heavy oil is becoming more and more demanding, and the coking rate is also increasing. How to improve or develop efficient coking regeneration technology for catalysts with less investment has always been the research and pursuit goal in the field of heavy oil catalytic conversion.

[0003] Commonly used catalyst coking regeneration methods include single-stage regeneration and two-stage regeneration. Single-stage regeneration, due to its relatively simple structure and uncomplicated internal components, has been widely used in small and medium-sized catalytic cracking units. However, for large heavy oil catalytic cracking units, due to the large amount of coke burned, single-stage regeneration, even with increased regenerator diameter and height, increased catalyst storage, and coking time, struggles to achieve the requirement of a carbon content below 0.1% in the regenerated catalyst. Furthermore, an excessively large regenerator diameter can cause severe catalyst backmixing within the fluidized bed, hindering uniform catalyst distribution and negatively impacting overall coking efficiency. For medium and large-sized heavy oil catalytic units, coking is carried out in two or more regenerators, avoiding the drawbacks of excessively high regeneration bed levels in single-stage regeneration structures, which lead to excessive pressure drop in the main flue gas system and increased energy consumption. Two-stage regeneration is superior to single-stage regeneration, with lower total catalyst storage and coking time. While patents for multi-stage regeneration and circulating fluidized bed regeneration have been developed in recent years, there are currently no industrial application examples domestically or internationally, limiting their practicality.

[0004] There are many technologies related to two-stage regeneration, the most typical being the RCC two-stage countercurrent regeneration technology disclosed in US4299687 and the ROCC-V coaxial two-stage countercurrent regeneration technology disclosed in Chinese Patent 95210840.2. The RCC structure consists of a first regenerator and a second regenerator arranged vertically. The first regenerator is located at the top, and the second regenerator at the bottom. The catalyst to be generated from the reactor first enters the upper part of the first regenerator, where it comes into countercurrent contact with the flue gas from the second regenerator and the fresh main air from the bottom of the first regenerator for coking. The semi-regenerated catalyst flows into the bottom of the second regenerator by gravity through the catalyst inclined tube, where it comes into contact with another stream of fresh main air for coking. The semi-regenerated catalyst inlet of the second regenerator in the RCC is lower than the regenerated catalyst outlet; therefore, the second regenerator is not strictly a countercurrent regeneration system. A key feature of the RCC is that the oxygen-containing flue gas from the second regenerator enters the first regenerator to continue participating in coking. Two-stage regeneration can improve regeneration efficiency and meet the requirements of large-scale equipment. However, since the catalyst to be regenerated enters the first regenerator through an inclined tube, the relatively high position of the first regenerator determines that the settling tank is also much taller. The settling tank height is generally more than 20m higher than that of a conventional high-low parallel catalytic converter of the same scale, resulting in higher construction investment and maintenance costs, and making daily inspections inconvenient. The disadvantages of two-stage RCC regeneration are that the gas-solid contact efficiency is lower than that of a fast bed, the total regenerator capacity is large, resulting in a large pressure drop in the flue gas system and lower flue gas pressure recovery.

[0005] CN1109091C and CN1221022A both disclose a two-stage overlapping regeneration technology for heavy oil fluidized catalytic conversion. Their regeneration process and the arrangement of the two regenerators are similar to the RCC technology disclosed in US4299687, and they also suffer from the problem of high investment due to the relatively high height of the RCC reactor regenerator. CN1109091C and CN1221022A feature significant innovations in the internal structure of the regenerator, connecting the two regenerators with a low-pressure-drop distribution plate. This technology is suitable for regenerating catalysts from inferior raw materials with high heavy metal content, especially vanadium content greater than 10 ppm, effectively reducing heavy metal pollution and catalyst consumption. However, in already operational units, the primary and secondary regeneration processes are typically supplied by the same main fan, resulting in a high pressure difference between the two processes. This leads to a large pressure drop in the main flue gas system, which is detrimental to the recovery of flue gas pressure energy. Summary of the Invention

[0006] To address the technical problems of low gas-solid contact efficiency, large total regenerator capacity, and large flue gas system pressure drop in existing technologies, which are not conducive to the recovery of flue gas pressure energy, this invention provides a fluidized bed multi-stage coke regeneration device and regeneration method.

[0007] The fluidized bed multi-stage coke regeneration device provided by the present invention includes a first regenerator, a second regenerator, and a third regenerator arranged coaxially from bottom to top and connected sequentially. The diameter of the three regenerators increases sequentially from bottom to top, and the connection is transitioned by a conical section. The bottom of the first regenerator is provided with a first main air distributor, and a first pre-catalyst inlet inclined pipe is provided on the side wall of the first regenerator above but near the first main air distributor. A first pre-catalyst inlet slide valve is provided on the first pre-catalyst inlet inclined pipe. A low pressure drop large-hole distribution plate is provided at the connection between the top of the first regenerator and the bottom of the second regenerator. The bottom of the second regenerator is provided with a second main air distributor, and a second pre-catalyst inlet inclined pipe is provided on the side wall of the second regenerator above but near the second main air distributor. A second pre-catalyst inlet slide valve is provided on the second pre-catalyst inlet inclined pipe.

[0008] The lower part of the third regenerator is provided with a cylindrical partition tube. Both ends of the partition tube are open. A gap is maintained between the lower end of the partition tube and the inner wall of the bottom of the third regenerator. The partition tube divides the lower part of the third regenerator into an internal flow guide area inside the partition tube and an annular flow guide area between the outer wall of the partition tube and the inner wall of the third regenerator cylinder.

[0009] The second regenerator is equipped with a catalyst dilute phase delivery pipe that extends entirely into the partitioned cylinder of the third regenerator. At the top of the catalyst dilute phase delivery pipe is a catalyst distributor located inside the partitioned cylinder that sprays catalyst into the lower part of the third regenerator. A third main air distributor is located inside the partitioned cylinder and at the bottom of the third regenerator. A fourth main air distributor is located inside the annular guide zone and at the bottom of the third regenerator. An inclined pipe for regenerating catalyst outlet is located above the fourth main air distributor and on the cylinder wall of the third regenerator where the annular guide zone is located.

[0010] Within the annular flow guide zone, at the bottom of the third regenerator and above the fourth main air distributor, a first regeneration circulation pipe is also provided on the cylinder wall of the third regenerator, which is connected to the bottom of the first regenerator. A first regeneration circulation slide valve is provided on the first regeneration circulation pipe. A cyclone separator is provided at the top of the third regenerator and above the partition cylinder. The exhaust port of the cyclone separator is connected to the regeneration flue gas outlet at the top of the third regenerator, and the lower part of the cyclone separator extends into the partition cylinder.

[0011] As an improvement, a second regeneration circulation pipe is provided on the inner wall of the partition cylinder near the bottom of the third regenerator, which is connected to the bottom of the second regenerator. A second regeneration circulation slide valve is provided on the second regeneration circulation pipe. The second regeneration circulation pipe is mainly used as an auxiliary measure to regulate the temperature at the bottom of the second regenerator.

[0012] As an improvement, a regenerated catalyst degassing tank is installed on the inclined pipe at the outlet of the regenerated catalyst. A degassing return pipe is located at the top of the regenerated catalyst degassing tank, returning the gas to the third regenerator. The bottom of the regenerated catalyst degassing tank is the outlet for the regenerated degassing catalyst. The regenerated catalyst degassing tank is mainly used to remove the flue gas entrained by the regenerated catalyst.

[0013] As an improvement, a fifth main air distributor is installed at the inlet of the catalyst dilute phase delivery pipe below the upper part of the second regenerator. It is mainly used to enhance the regeneration of the catalyst in the second regenerator and regulate the linear velocity of the catalyst dilute phase delivery pipe, so as to facilitate the rapid entry of the catalyst into the third regenerator.

[0014] When the regeneration device of the present invention is in operation, the catalyst to be recycled from the stripping section of the reaction system enters the regeneration device in two separate streams:

[0015] The first batch of awaiting catalyst enters the first regenerator through the first awaiting catalyst inlet inclined tube and mixes with the circulating high-temperature regenerated catalyst from the third regenerator that enters the first regenerator through the first regeneration circulation inclined tube. After reaching a high mixing temperature, it comes into contact with the first coking main air that enters the first regenerator through the first main air distributor. The coking produces a large amount of flue gas that agitates the catalyst to form the first rapid fluidized bed.

[0016] The high-temperature flue gas generated by the combustion of carbon attached to the first-path catalyst carries the mixed catalyst from the first regenerator upward through the low-pressure-drop large-hole distribution plate into the second regenerator. At the bottom of the second regenerator, it comes into contact with the second coking main air entering the second regenerator through the second main air distributor for heat exchange. The high-temperature gas-solid two-phase flow after heat exchange comes into contact with the second-path catalyst entering the second regenerator through the second-path catalyst inlet inclined tube for coking. The coking generates a large amount of flue gas that agitates the catalyst to form a second fast fluidized bed.

[0017] The high-temperature flue gas generated by the first and second rapid fluidized beds carries the catalyst upwards through the catalyst dilute phase conveying pipe into the third regenerator compartment. It is then evenly sprayed into the compartment by the catalyst distributor, where it comes into countercurrent contact with the third coking main air entering the compartment via the third main air distributor, forming the third rapid fluidized bed. After being coked in the countercurrent flow, the catalyst flows downwards in the compartment and enters the annular guide zone, where it comes into parallel contact with the fourth coking main air entering the annular guide zone via the fourth main air distributor, and is coked again. The regenerated flue gas carrying the catalyst is separated from the catalyst particles by the cyclone separator and discharged through the regenerated flue gas outlet of the third regenerator. The regenerated catalyst is returned to the reaction system through the regenerated catalyst outlet inclined pipe.

[0018] The present invention also provides a fluidized bed multi-stage coke regeneration method, comprising the following steps:

[0019] 1) The first-stage catalyst and the circulating high-temperature regenerated catalyst from the annular guide zone of the third regenerator are mixed in the first regenerator. After reaching a high mixing temperature, they come into contact with the first coking main air entering the first regenerator in the same direction for co-flow coking. The catalyst undergoes incomplete regeneration. The coking produces a large amount of CO-rich flue gas that agitates the catalyst to form the first fast fluidized bed.

[0020] 2) The high-temperature flue gas from the first fast fluidized bed carries the mixed catalyst from the first regenerator upward into the second regenerator, where it contacts and exchanges heat with the second coking main air entering the second regenerator. The high-concentration CO in the first regenerator reacts exothermically with the oxygen in the second coking main air, and part of the high-concentration CO in the flue gas of the first regenerator is converted into CO2. The heat released by the reaction rapidly increases the gas-solid mixing temperature at the bottom of the second regenerator. The high-temperature gas-solid two-phase flow after heat exchange contacts the second path of the spent catalyst entering the second regenerator in a co-current coking process. The second path of the spent catalyst undergoes coking regeneration, generating a large amount of CO and CO2. The coking releases a large amount of heat, and the large amount of flue gas generated by the coking agitates the catalyst to form the second fast fluidized bed.

[0021] 3) The high-temperature flue gas generated by the first and second fast fluidized beds carries the catalyst upward through the catalyst dilute phase conveying pipe into the partitioned cylinder of the third regenerator bed. It is then uniformly sprayed into the third regenerator by the catalyst distributor, where it comes into countercurrent contact with the third coking main air entering the partitioned cylinder of the third regenerator for countercurrent coking, forming the third fast fluidized bed. After countercurrent coking, the catalyst flows downward in the partitioned cylinder and enters the annular guide zone, where it flows upward and comes into parallel contact with the fourth coking main air entering the annular guide zone for parallel coking again. The regenerated flue gas carrying the catalyst is separated from the catalyst particles by the cyclone separator and discharged through the regenerated flue gas outlet of the third regenerator. The regenerated catalyst is returned to the reaction system through the regenerated catalyst outlet inclined pipe.

[0022] As an improvement, a high-temperature regeneration catalyst from the partitioned cylinder of the third regenerator is introduced into the second regenerator to regulate the bottom temperature of the second fast fluidized bed.

[0023] As an improvement, a fifth stream of coking air is introduced at the inlet of the catalyst dilute phase conveying pipe below the upper part of the second regenerator. This is used to increase the coking intensity of the second regenerator and adjust the linear velocity of the catalyst dilute phase conveying pipe, which is conducive to the rapid entry of the catalyst into the third regenerator.

[0024] The coking intensity of the first rapid fluidized bed is approximately 700 kg / ht, significantly improving the catalyst regeneration rate. Compared to conventional single-stage or multi-stage countercurrent regeneration processes, the coking intensity is increased by 4 to 6 times.

[0025] The second-stage recycled catalyst accounts for 65-85% of the total recycled catalyst volume.

[0026] The flue gas delivery pipe of the second fast fluidized bed is designed with a linear velocity of 7–15 m / s. Excessively high delivery linear velocity can easily lead to catalyst wear, increased fine particle content, and consequently, increased catalyst consumption. Insufficient delivery linear velocity, on the other hand, is detrimental to the uniform injection of the gas-solid two-phase mixture from the second fast fluidized bed into the third fast fluidized bed after passing through the distributor.

[0027] The third rapid fluidized bed is a turbulent bed with an apparent linear velocity of 0.5–1.2 m / s in the gas phase.

[0028] The third rapid fluidized bed can employ either full regeneration with high oxygen content or incomplete regeneration (oxygen-deficient regeneration), depending on the weight of the processed raw materials or the overall steam grade requirements of the plant. If the third rapid fluidized bed uses oxygen-deficient regeneration, the CO-rich regenerated flue gas passes through a subsequent CO incinerator or CO boiler, where CO undergoes an exothermic reaction to generate CO2 at a higher temperature. A steam generator can be installed in the annular guide zone of the third regenerator to produce medium- and high-pressure steam, or a superheated tube can be installed to produce medium- and high-pressure (3.5 MPa) or even high-pressure (10.0 MPa) steam. The generated high-pressure (10.0 MPa) steam then drives the back-pressure turbine, achieving energy saving and consumption reduction.

[0029] The features of this invention are described below:

[0030] 1) This invention employs a two-stage rapid fluidized bed regeneration system, with coking air and regenerating agent distributed in stratified layers. The quantity or level of the first and second rapid fluidized beds is controlled by separately controlling the valve openings on the external circulation regeneration catalyst delivery lines.

[0031] 2) The purpose of setting up the first fast fluidized bed in this invention is to use the high-temperature circulating regenerated catalyst and the exothermic reaction of the spent catalyst burning carbon to raise the temperature of the main air of the second fast fluidized bed. Under the same ignition temperature of the spent catalyst in the second fast fluidized bed, the amount of regenerated catalyst circulating is reduced, thereby increasing the carbon content of the unit catalyst in the second fast fluidized bed, reducing the amount of catalyst stored, and increasing the coking intensity.

[0032] 3) By controlling the opening degree of the valve on the first catalyst delivery line, the amount of coke burned in the first fast fluidized bed is controlled, the amount of coke burning air entering the first fast fluidized bed is controlled, and the CO content in the coke burning flue gas of the first fast fluidized bed is controlled, thereby indirectly controlling the temperature of the coke burning main air sprayed from the second fast fluidized bed.

[0033] 4) By controlling the valve opening on the external circulation regeneration catalyst delivery line of the first fast fluidized bed, the catalyst mixing temperature entering the first fast fluidized bed is controlled, thereby controlling the initial combustion temperature and coking intensity of the first fast fluidized bed.

[0034] 5) The high-temperature flue gas rich in CO from the first fast fluidized bed passes through the low pressure drop distribution plate of the first fast fluidized bed and mixes with the coking main air from the second fast fluidized bed. The CO in the flue gas reacts with the O2 in the second fluidized main air to generate CO2, which in turn releases a large amount of heat, thereby significantly increasing the temperature of the main air in the second fast fluidized bed. The main air with the increased temperature then comes into contact with the second path of the waiting catalyst from the settling tank to burn the coke.

[0035] 6) The second-stage regenerated catalyst enters from the bottom of the second fast fluidized bed, and the second-stage circulating regenerated catalyst is extracted from the bottom of the third fast fluidized bed and returned to the bottom of the second fast fluidized bed to help control the initial combustion temperature of the regenerated catalyst in the second fluidized bed.

[0036] 7) In the first and second rapid fluidized beds of this invention, the coking air and catalyst are regenerated in a co-current process from bottom to top. The carbon content on the catalyst gradually decreases from bottom to top, and the oxygen content in the flue gas gradually decreases. In the third rapid fluidized bed, the third coking air flows upward from the bottom of the third rapid fluidized bed. After the catalyst and flue gas of the second rapid fluidized bed are sprayed out by the catalyst distributor, the catalyst flows downward and comes into counter-current contact with the third main air of the third rapid fluidized bed for coking. After being deflected into the annular guide zone, it comes into parallel contact with the fourth main coking air for coking.

[0037] 8) The first fast fluidized bed adopts incomplete regeneration. The purpose is to use the CO in the flue gas of the first fast fluidized bed to react chemically with the main air of the second fast fluidized bed to generate CO2. The heat released is used to heat the main air of the second fast fluidized bed and the catalyst to be generated in the second fast fluidized bed.

[0038] The beneficial effects of this invention are as follows: This invention employs a three-stage regenerator arranged coaxially in series, utilizing multi-stage series regeneration and zoned coking of the spent catalyst for exothermic reaction. This reduces the amount of hot catalyst circulating, thereby reducing the total amount of material in the regenerator, increasing the average chemical kinetic rate, and enhancing the regeneration process. Simultaneously, it allows for separate feeding of the spent catalyst from the bottom of the regenerator, reducing the height of the settling tank, shortening the oil and gas pipeline at the top of the settling tank, and lowering engineering investment. This invention is also applicable to fields such as pulverized coal fluidized bed pyrolysis. Attached Figure Description

[0039] The invention will now be further described with reference to the accompanying drawings.

[0040] Figure 1 This is a schematic diagram of one structure of the device of the present invention.

[0041] In the diagram: 1-First regenerator, 2-First main air distributor, 3-First prepared catalyst inlet inclined tube, 4-First prepared catalyst inlet slide valve, 5-Low pressure drop large orifice distribution plate, 6-First regeneration circulation pipe, 7-First regeneration circulation slide valve, 8-Second main air distributor, 9-Second regenerator, 10-Second prepared catalyst inlet slide valve, 11-Second prepared catalyst inlet inclined tube, 12-Second regeneration circulation slide valve, 13-Second regeneration circulation pipe, 14-Fifth main air distributor, 15-Regenerated catalyst outlet inclined tube, 16-Regenerated degassing catalyst outlet, 17-Regenerated catalyst degassing tank, 18-Degassing return pipe, 19-Third main air distributor, 20-Catalyst dilute phase conveying pipe, 21-Catalyst distributor, 22-Third regenerator, 23-Cyclone separator, 24-Regenerated flue gas collection chamber, 25-Regenerated flue gas outlet, 26-Divider cylinder, 27-Fourth main air distributor. Detailed Implementation

[0042] The invention will now be further described with reference to the accompanying drawings.

[0043] like Figure 1 As shown, the fluidized bed multi-stage coke regeneration device provided by the present invention includes a first regenerator 1, a second regenerator 9 and a third regenerator 22 arranged coaxially from bottom to top and connected in sequence. The diameter of the three regenerators increases sequentially from bottom to top, and the connection is transitioned by a conical section.

[0044] The first regenerator 1 is provided with a first main air distributor 2 at its bottom. The first catalyst inlet inclined pipe 3 is provided on the side wall of the first regenerator 1 at a position higher than but close to the first main air distributor 2. The first catalyst inlet inclined pipe 3 is provided with a first catalyst inlet slide valve 4. The connection between the first regenerator 1 and the second regenerator 9 is provided with a low pressure drop large orifice distribution plate 5.

[0045] The second regenerator 9 is provided with a second main air distributor 8 at the bottom. The second regenerator 9 is provided with a second catalyst inlet inclined pipe 11 on its side wall, which is higher than but close to the second main air distributor 8. The second catalyst inlet inclined pipe 11 is provided with a second catalyst inlet slide valve 10. The second regenerator 9 is provided with a fifth main air distributor 14 at the inlet below the catalyst dilute phase conveying pipe 20.

[0046] The lower part of the third regenerator 22 is provided with a cylindrical partition cylinder 26. Both the upper and lower ends of the partition cylinder 26 are open. A gap is maintained between the lower end of the partition cylinder 26 and the inner wall of the bottom of the third regenerator 22 as a material flow channel. The partition cylinder 26 divides the lower part of the third regenerator 22 into an internal guide zone inside the partition cylinder 26 and an annular guide zone between the outer wall of the partition cylinder 26 and the inner wall of the third regenerator 22. The bottom of the partition cylinder 26 can be connected to the bottom of the third regenerator 22 by a vertical grid, and the upper part of the partition cylinder 26 can be connected to the inner wall of the third regenerator 22 by a horizontal grid.

[0047] The second regenerator 9 is equipped with a catalyst dilute phase delivery pipe 20 that extends entirely into the partition cylinder 26. The top of the catalyst dilute phase delivery pipe 20 is equipped with a catalyst distributor 21 located inside the partition cylinder 26 that sprays catalyst to the bottom of the third regenerator. Inside the partition cylinder 26 and at the bottom of the third regenerator 22, there is a third main air distributor 19. Inside the annular guide zone and at the bottom of the third regenerator 22, there is a fourth main air distributor 27. Above the fourth main air distributor 27 and on the cylinder wall of the third regenerator 22 where the annular guide zone is located, there is a regenerated catalyst outlet inclined pipe 15.

[0048] The regenerated catalyst outlet inclined pipe 15 is equipped with a regenerated catalyst degassing tank 17. The top of the regenerated catalyst degassing tank 17 is equipped with a degassing return pipe 18 to return to the third regenerator 22. The bottom of the regenerated catalyst degassing tank 17 is the regenerated degassing catalyst outlet 16.

[0049] Within the annular flow guide zone, at the bottom of the third regenerator 22 and above the fourth main air distributor 27, the third regenerator 22 is also provided with a first regeneration circulation pipe 6 connected to the bottom of the first regenerator 1, and a first regeneration circulation slide valve 7 is provided on the first regeneration circulation pipe 6; within the partition cylinder 26, near the bottom of the third regenerator 22, a second regeneration circulation pipe 13 is provided to the bottom of the second regenerator 9, and a second regeneration circulation slide valve 12 is provided on the second regeneration circulation pipe 13.

[0050] A cyclone separator 23 is provided at the top of the third regenerator 22 and above the partition cylinder 26. The exhaust port of the cyclone separator 23 is connected to the regenerated flue gas collection chamber 24. The regenerated flue gas collection chamber 24 is connected to the regenerated flue gas outlet 25 at the top of the third regenerator 22. The lower part of the cyclone separator 23 extends into the partition cylinder 26.

[0051] The following is combined Figure 1 The fluidized bed multi-stage coke regeneration method of the present invention will be described, and the coke regeneration method of the present invention includes the following steps:

[0052] 1) The first-path spent catalyst enters the first regenerator 1 through the first spent catalyst inlet inclined pipe 3 and mixes with the circulating high-temperature regenerated catalyst from the annular guide zone of the third regenerator 22 through the first regeneration circulation pipe 6 in the first regenerator 1. After reaching a high mixing temperature, it comes into contact with the first coking main air entering the first regenerator 1 through the first main air distributor 2 and co-flows coking. The spent catalyst undergoes incomplete regeneration. The coking produces a large amount of CO-containing flue gas, which agitates the catalyst to form the first fast fluidized bed.

[0053] 2) The high-temperature flue gas from the first fast fluidized bed carries the mixed catalyst in the first regenerator 1 upward through the low-pressure drop large-hole distribution plate 5 into the second regenerator 9. It comes into contact with the second coking main air entering the second regenerator 9 through the second main air distributor 8 and the circulating high-temperature regenerated catalyst from the partition cylinder 26 of the third regenerator 22 entering the second regenerated circulation pipe 13 for heat exchange. The high-temperature gas-solid two-phase flow after heat exchange comes into contact with the second path of the prepared catalyst entering the second regenerated catalyst in ... first regenerated catalyst in the first regenerated catalyst in the first regenerated catalyst in the first regenerated catalyst in the first regenerated catalyst in the first regenerated catalyst in the first regenerated catalyst in the first regenerated catalyst in the first regenerated catalyst in the first regenerated catalyst in the first regenerated catalyst in the first regenerated catalyst in the first regenerated catalyst in the first regenerated catalyst in the first regenerated catalyst in the first regenerated catalyst in

[0054] 3) The high-temperature flue gas generated by the first and second fast fluidized beds, carrying the catalyst, is transported upwards by the fifth main air flow from the fifth main air distributor 14 into the second regenerator 9, and then enters the partition cylinder 26 of the third regenerator 22 via the catalyst dilute phase conveying pipe 20. It is then evenly sprayed downwards into the partition cylinder 26 of the third regenerator 22 via the catalyst distributor 21, where it comes into countercurrent contact with the third coking main air flow entering the partition cylinder 26 of the third regenerator 22 via the third main air distributor 19, resulting in countercurrent coking and forming the third fast fluidized bed. After countercurrent coking, the catalyst flows downwards within the partition cylinder 26 and enters the annular flow. The fourth coking main air, which enters the annular guide zone through the fourth main air distributor 27, comes into parallel contact with the fourth coking main air entering the annular guide zone for coking again. The regenerated flue gas carrying the catalyst is separated from the catalyst particles by the cyclone separator 23 and enters the regenerated flue gas collection chamber 24. Finally, it is discharged through the regenerated flue gas outlet 25 of the third regenerator 22. The regenerated catalyst after regeneration enters the regenerated catalyst degassing tank 17 through the regenerated catalyst outlet inclined pipe 15 for degassing. The degassed gas returns to the third regenerator 22 through the degassing return pipe 18. The degassed regenerated catalyst returns to the reaction system through the regenerated degassing catalyst outlet 16.

[0055] The coking intensity of the first fast fluidized bed is about 700 kg / ht, the second path of spent catalyst accounts for 65-85% of the total spent catalyst circulation, the design linear velocity of the flue gas delivery pipe of the second fast fluidized bed is 7-15 m / s, and the apparent linear velocity of the gas phase of the third fast fluidized bed is 0.5-1.2 m / s.

Claims

1. A fluidized bed multi-stage coke regeneration device, characterized in that: The device includes a first regenerator, a second regenerator, and a third regenerator, which are coaxially arranged and connected sequentially from bottom to top. The diameter of the three regenerators increases sequentially from bottom to top, and the connection is transitioned by a conical section. The first regenerator has a first main air distributor at its bottom, and a first pre-catalyst inlet inclined pipe is located on the side wall of the first regenerator, higher than but close to the first main air distributor. A first pre-catalyst inlet slide valve is located on the first pre-catalyst inlet inclined pipe. A low-pressure-drop large-hole distribution plate is located at the connection between the top of the first regenerator and the bottom of the second regenerator. The second regenerator has a second main air distributor at its bottom, and a second pre-catalyst inlet inclined pipe is located on the side wall of the second regenerator, higher than but close to the second main air distributor. A second pre-catalyst inlet slide valve is located on the second pre-catalyst inlet inclined pipe. The lower part of the third regenerator is provided with a cylindrical partition tube. Both ends of the partition tube are open. A gap is maintained between the lower end of the partition tube and the inner wall of the bottom of the third regenerator. The partition tube divides the lower part of the third regenerator into an internal flow guide area inside the partition tube and an annular flow guide area between the outer wall of the partition tube and the inner wall of the third regenerator cylinder. The second regenerator is equipped with a catalyst dilute phase delivery pipe that extends entirely into the partitioned cylinder of the third regenerator. At the top of the catalyst dilute phase delivery pipe is a catalyst distributor located inside the partitioned cylinder that sprays catalyst into the lower part of the third regenerator. A third main air distributor is located inside the partitioned cylinder and at the bottom of the third regenerator. A fourth main air distributor is located inside the annular guide zone and at the bottom of the third regenerator. An inclined pipe for regenerating catalyst outlet is located above the fourth main air distributor and on the cylinder wall of the third regenerator where the annular guide zone is located. Within the annular flow guide zone, at the bottom of the third regenerator and above the fourth main air distributor, a first regeneration circulation pipe is also provided on the cylinder wall of the third regenerator, which is connected to the bottom of the first regenerator. A first regeneration circulation slide valve is provided on the first regeneration circulation pipe. A cyclone separator is provided at the top of the third regenerator and above the partition cylinder. The exhaust port of the cyclone separator is connected to the regeneration flue gas outlet at the top of the third regenerator, and the lower part of the cyclone separator extends into the partition cylinder.

2. The fluidized bed multi-stage coke regeneration device according to claim 1, characterized in that: The partitioned cylinder has a second regeneration circulation pipe on the cylinder wall near the bottom of the third regenerator, which is connected to the bottom of the second regenerator. The second regeneration circulation pipe is equipped with a second regeneration circulation slide valve.

3. The fluidized bed multi-stage coke regeneration device according to claim 1, characterized in that: The regenerated catalyst outlet inclined tube is equipped with a regenerated catalyst degassing tank. The top of the regenerated catalyst degassing tank is equipped with a degassing return pipe that returns to the third regenerator. The bottom of the regenerated catalyst degassing tank is the regenerated degassing catalyst outlet.

4. The fluidized bed multi-stage coke regeneration device according to claim 1, characterized in that: A fifth main air distributor is installed at the upper part of the second regenerator and at the inlet below the catalyst dilute phase conveying pipe.

5. A fluidized bed multi-stage coke regeneration method, characterized in that... Includes the following steps: 1) The first-stage catalyst and the circulating high-temperature regenerated catalyst from the annular guide zone of the third regenerator are mixed in the first regenerator. After reaching a high mixing temperature, they come into contact with the first coking main air entering the first regenerator in the same direction for co-flow coking. The catalyst undergoes incomplete regeneration. The coking produces a large amount of CO-rich flue gas that agitates the catalyst to form the first fast fluidized bed. 2) The high-temperature flue gas from the first fast fluidized bed carries the mixed catalyst from the first regenerator upward into the second regenerator, where it contacts and exchanges heat with the second coking main air entering the second regenerator. The high-concentration CO in the first regenerator reacts exothermically with the oxygen in the second coking main air, and part of the high-concentration CO in the flue gas of the first regenerator is converted into CO2. The heat released by the reaction rapidly increases the gas-solid mixing temperature at the bottom of the second regenerator. The high-temperature gas-solid two-phase flow after heat exchange contacts the second path of the spent catalyst entering the second regenerator in a co-current coking process. The second path of the spent catalyst undergoes coking regeneration, generating a large amount of CO and CO2. The coking releases a large amount of heat, and the large amount of flue gas generated by the coking agitates the catalyst to form the second fast fluidized bed. 3) The high-temperature flue gas generated by the first and second fast fluidized beds carries the catalyst upward through the catalyst dilute phase conveying pipe into the partitioned cylinder of the third regenerator bed. It is then uniformly sprayed into the third regenerator by the catalyst distributor, where it comes into countercurrent contact with the third coking main air entering the partitioned cylinder of the third regenerator for countercurrent coking, forming the third fast fluidized bed. After countercurrent coking, the catalyst flows downward in the partitioned cylinder and enters the annular guide zone, where it flows upward and comes into parallel contact with the fourth coking main air entering the annular guide zone for parallel coking again. The regenerated flue gas carrying the catalyst is separated from the catalyst particles by the cyclone separator and discharged through the regenerated flue gas outlet of the third regenerator. The regenerated catalyst is returned to the reaction system through the regenerated catalyst outlet inclined pipe.

6. The fluidized bed multi-stage coke regeneration method according to claim 5, characterized in that: A high-temperature regeneration catalyst from the partitioned cylinder of the third regenerator is introduced into the second regenerator to regulate the bottom temperature of the second fast fluidized bed.

7. The fluidized bed multi-stage coke regeneration method according to claim 5, characterized in that: A fifth stream of coking air is introduced at the upper part of the second regenerator and below the inlet of the catalyst dilute phase conveying pipe. This is used to increase the coking intensity of the second regenerator and adjust the linear velocity of the catalyst dilute phase conveying pipe, which facilitates the rapid entry of the catalyst into the third regenerator.

8. The fluidized bed multi-stage coke regeneration method according to any one of claims 5 to 7, characterized in that: The scorching intensity of the first rapid fluidized bed is approximately 700 kg / ht.

9. The fluidized bed multi-stage coke regeneration method according to any one of claims 5 to 7, characterized in that: The second-stage recycled catalyst accounts for 65-85% of the total recycled catalyst volume.

10. The fluidized bed multi-stage coke regeneration method according to any one of claims 5 to 7, characterized in that: The flue gas delivery pipe of the second rapid fluidized bed is designed to have a linear velocity of 7-15 m / s.

11. The fluidized bed multi-stage coke regeneration method according to any one of claims 5 to 7, characterized in that: The third rapid fluidized bed is a turbulent bed with an apparent linear velocity of 0.5–1.2 m / s in the gas phase.

12. The fluidized bed multi-stage coke regeneration method according to any one of claims 5 to 7, characterized in that: The third rapid fluidized bed can be fully regenerated or partially regenerated.

Images